1. Field of the Invention
This invention relates to a wheel hub-and-bearing set assembly, more particularly to a wheel hub-and-bearing set assembly for a roller skate.
2. Description of the Related Art
A conventional wheel hub-and-bearing set assembly for a roller skate normally includes bearings, a bearing spacer that separates bearing inner rings of the bearings, and a hub body adapted to be connected to a tire and having bearing pockets in its center and sides that separate outer rings of the bearings and that are disposed around the bearing spacer. The bearings are mounted securely in the bearing pockets between the hub body at their outer ring and the bearing spacer at their inner ring, and usually have a pair of sealing caps mounted on two opposite sides of the hub body for preventing dirt from reaching the bearings.
The conventional wheel hub-and-bearing set assembly is disadvantageous as it is difficult to align the bearings with the bearing pockets on its outer ring and the spacer on it inner ring, while keeping the bearings true to the center and middle line of the wheel, as well as to the respective inner and outer rings. Incorrect alignment of all these different parts results in wobble of the wheel around its rotation center and consequently a pronounced wear of bearing as well as wheel tire, while also the outer rings of the bearings get distorted. In addition, since the bearings are tightly secured in the bearing pockets between the hub body and the bearing spacer, removal of the bearings from the bearing pockets is difficult to conduct. As a consequence, the service life of the wheel and the bearings is sharply reduced, while the competitive skaters cannot achieve the utmost attainable speed.